Tolerance of the fœtal allograft by the maternal immune system in human is a complex multi-factorial mechanism. It has been strongly presumed to involve the CD95/CD95-L apoptotic system, HLA-G, IDO, ILF ... [more ▼]

Tolerance of the fœtal allograft by the maternal immune system in human is a complex multi-factorial mechanism. It has been strongly presumed to involve the CD95/CD95-L apoptotic system, HLA-G, IDO, ILF or the Th1/Th2 balance. This last theory proposes that the shift of the Thl/Th2 balance toward Th2 reduces the inflammatory immune responses and so the probability of foetus rejection. A very interesting question is to know how conceptus could influence this Th1/Th2 balance. Some years ago, our group has demonstrated the apparition, during pregnancy, of a different growth hormone, the placental growth hormone (hPGH = hGH-V), secreted by placenta and which progressively replaces the pituitary growth hormone (hGH-N). Could this replacement of hGH-N by hPGH exert an effect on the Th1/Th2 balance, and so could this contribute to protect the conceptus against rejection ? To investigate this possibility, we couldn't perform usual FACS cell-surface marker analysis techniques because, at our knowledge, no discriminating Th1 and Th2 specific membrane protein exists. The only available way was to study the cytokine production pattern. So, beside cytokines's, the mRNAs production tell us about the cellular Thl/Th2 balance status. We investigated here peripheral blood mononuclear cells, which are the maternal immune cells coming in contact to trophoblastic cells which limit foetal tissues. Blood cells were isolated from women but also from men. Specific mRNA were quantified in a multi-probe RNase Protection assay after short-term cultures. The results show that : 1. hGHs may act on cytokine mRNAs production. 2. hPGH may act differently as hGH-N. 3. men/women cell responses difference is not higher than inter-individual variations. 4. cells do not seem to respond in a clear Th1/Th2 way ; GHs seem to act differently accordingly to the cytokine considered. 5. high inter-individual variability exists, confirming that peripheral blood mononuclear cells, often describe as mainly quiescent cells, could possess very different immune response capabilities, certainly in correlation with the immune past of the blood donor. So hPGH appear not to act directly on the Th1/Th2 balance but well on the secretion of given cytokines. [less ▲]

In prostate cancer therapy, the components of the cell death could play an important role: it is conceivable that targeted tranfer of such genes into prostatic cells could be useful. In our laboratory, a ... [more ▼]

In prostate cancer therapy, the components of the cell death could play an important role: it is conceivable that targeted tranfer of such genes into prostatic cells could be useful. In our laboratory, a new gene, the CIPAR1 (fro Castration Induced Prostatic Apoptosis Related 1), was identified by Marc Bruyninx. This gene is upregulated when the rat prostate is induced to undergo apoptosis. To learn more about the cellular function of the CIPAR1, we have decided to establish a stable cell line inducible for the expression of CIPAR1 using the "Tet-On expression system" of Clontech. Thanks to this system, we now possess a Tet-On cell line expressing CIPAR1 under Tet control. It has a high expression level of CIPAR1 and this expression can be quantitatively regulated. We hope that this stable cell line will let us elucidate the cellular functions of CIPAR1. [less ▲]

Using microsatellite genotyping in Barbus meridionalis, we tried to assess the identity of fathers of progeny produced during four experimental polyandrous crosses involving the same four males and one or ... [more ▼]

Using microsatellite genotyping in Barbus meridionalis, we tried to assess the identity of fathers of progeny produced during four experimental polyandrous crosses involving the same four males and one or two females. The pooled analysis revealed that males had significantly different reproductive successes. We found no conspicuous causes explaining differential reproductive success in the behavioural data or in the physical characteristics of the males but a genetic determinism is the most parsimonious hypothesis to account for this variability. We argue that this conclusion is compatible with the hypothesis that the reproductive strategy of barbels, which involves large aggregations of males, is a result of sexual selection. This study provides guidelines for future interspecific crosses and constitutes the preliminary experiment of an investigation of the origin of a hybrid zone between Barbus barbus and Barbus meridionalis. [less ▲]

The Einstein Cross, Q 2237+0305, has been photometrically observed in four bands on two successive nights at NOT (La Palma, Spain) in October 1995. Three independent algorithms have been used to analyse ... [more ▼]

The Einstein Cross, Q 2237+0305, has been photometrically observed in four bands on two successive nights at NOT (La Palma, Spain) in October 1995. Three independent algorithms have been used to analyse the data: an automatic image decomposition technique, a CLEAN algorithm and the new MCS deconvolution code. The photometric and astrometric results obtained with the three methods are presented. No photometric variations were found in the four quasar images. Comparison of the photometry from the three techniques shows that both systematic and random errors affect each method. When the seeing is worse than 1farcs0 , the errors from the automatic image decomposition technique and the Clean algorithm tend to be large (0.04-0.1 magnitudes) while the deconvolution code still gives accurate results (1sigma error below 0.04) even for frames with seeing as bad as 1farcs7 . Reddening is observed in the quasar images and is found to be compatible with either extinction from the lensing galaxy or colour dependent microlensing. The photometric accuracy depends on the light distribution used to model the lensing galaxy. In particular, using a numerical galaxy model, as done with the MCS algorithm, makes the method less seeing dependent. Another advantage of using a numerical model is that eventual non-homogeneous structures in the galaxy can be modeled. Finally, we propose an observational strategy for a future photometric monitoring of the Einstein Cross. Based on observations obtained at NOT, La Palma. [less ▲]

in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (1998, November 01)

The IMAGE FUV-SI is simultaneously imaging auroras at 121.8 nm and 135.8 nm. The spectrograph design challenge is the efficient rejection of the intense Lyman-alpha emission at 121.6 nm while passing its ... [more ▼]

The IMAGE FUV-SI is simultaneously imaging auroras at 121.8 nm and 135.8 nm. The spectrograph design challenge is the efficient rejection of the intense Lyman-alpha emission at 121.6 nm while passing its Doppler-shifted component at 121.8 nm. The FUV-SI opto-mechanical design, analysis integration, and verification of performances against environment are discussed in this paper. In absence of STM environmental constraints at subsystem levels are derived analytically from F.E.M. and used for pre-qualifying optical subsystems. [less ▲]

Self-affine signals characterized by a defined Hurst (roughness) exponent H can be investigated through mobile averages. The density rho of crossing points between any two moving averages is a measure of ... [more ▼]

Self-affine signals characterized by a defined Hurst (roughness) exponent H can be investigated through mobile averages. The density rho of crossing points between any two moving averages is a measure of long-range power-law correlations in the signal. The method is compared to the detrended fluctuation analysis. We rake advantage of our findings in order to propose a practically powerful and accurate technique for determining H and apply it right away to cases with persistent or antipersistent correlations. [less ▲]

Rotating stall and surge, two instability mechanisms limiting the performance of aeroengines compressors, are studied on the third-order Moore–Greitzer model. The skewness of the compressor characteristic ... [more ▼]

Rotating stall and surge, two instability mechanisms limiting the performance of aeroengines compressors, are studied on the third-order Moore–Greitzer model. The skewness of the compressor characteristic, a single parameter shape signifier, is shown to determine the key qualitative properties of feedback control. [less ▲]